Can we always trust rhinomanometry?

Abstract

Objectives: Rhinomanometry before and after decongestion distinguishes a nasal airway organic stenosis from congestion of nasal mucosa in patients with nasal stuffiness. Together with rhinoscopy and patient history, it is used to decide if nasal surgery would benefit the patient. Rhinomanometry measurements should thus be reliable and reproducible. Materials and methods: We performed repetitive active anterior rhinomanometry in 9 persons during 5 months to test reproducibility of nasal airway resistance (NAR) over time. We also did test-retest measurements in several participants. Xylometazoline hydrochloride was applied in each nasal cavity to minimize effects of mucosal variation and the nasal cavity was examined with rhinoscopy. The participants evaluated subjective nasal stuffiness on a visual analogue scale (VAS). Results: The long term mean coefficient of variation (CV) of NAR over time was 27% for the whole group while the short term CV was 7 - 17% for test-retest within an hour. Mean NAR reduction after decongestion was 33%, but 13% of NAR values were not reduced after decongestion. Participants had difficulties estimating stuffiness on a VAS in 15% of the assessments, but there was no correlation between the VAS estimates and NAR. Conclusion: We found a high NAR variation over a period of five months. This implies low long-term rhinomanometry reproducibility and we suggest future research on standardised decongestion to increase the reproducibility.

Correlation between Subjective Nasal Patency and Intranasal Airflow Distribution

“…Multiple in vivo studies found that subjective nasal patency does not correlate with nasal resistance measured via rhinomanometry or the airspace minimal cross-sectional area (MCA) measured via acoustic rhinometry. 4,5,[8][9][10] This agrees with the concept that patients with NAO present due to a subjective perception of decreased patency rather than an objective reduction in nasal resistance. 32 Certainly, resistance is a related entity, but it remains a distinctly different variable than subjective patency, 9 which recent literature suggests may be more related to mucosal cooling.…”

“…The mechanism responsible for nasal airflow sensation remains incompletely understood. Multiple in vivo studies found that subjective nasal patency does not correlate with nasal resistance measured via rhinomanometry or the airspace minimal cross‐sectional area (MCA) measured via acoustic rhinometry 4,5,8‐10 . This agrees with the concept that patients with NAO present due to a subjective perception of decreased patency rather than an objective reduction in nasal resistance 32 .…”

“…Despite these efforts, NAO remains a diagnostic challenge due to inconsistencies between subjective symptoms and clinical exam, 3 as well as the lack of reliable symptomatic correlation with objective assessment of nasal function by methods such as rhinomanometry, peak nasal inspiratory flow (PNIF), and acoustic rhinometry. [4][5][6][7][8][9][10] Given that current objective methods do little to identify specific, clinically significant anatomical sites of obstruction, the diagnosis of NAO, the decision to proceed with surgery, and the selection of structures to target are often based on surgeon intuition. The development of better objective methods to guide decision making may help improve the success rate of NAO surgery, which has been deemed unsatisfactory by many otolaryngologists.…”

“…Many studies have aimed to improve diagnosis of this condition, with the goal of optimizing therapeutic outcomes. Despite these efforts, NAO remains a diagnostic challenge due to inconsistencies between subjective symptoms and clinical exam, 3 as well as the lack of reliable symptomatic correlation with objective assessment of nasal function by methods such as rhinomanometry, peak nasal inspiratory flow (PNIF), and acoustic rhinometry 4‐10 …”

Absolute quantification of chromosome copy numbers in the polyploid macronucleus of Tetrahymena thermophila at the single‐cell level

“…For this, both the MDS region and a unique IES (MIC‐specific) sequence proximity to the MDS region were examined by ddPCR in the same reaction using probes labeled with different fluorescence dyes, and then the IES copy number was subtracted from the MDS sequence copy number. Results from twofold serial dilutions of cell lysates (0.5–8 cell equivalents per reaction) showed significant linearity, R 2 = 0.998 ( p < 0.0001), with low coefficient of variation (CV) values of about 10% (Thulesius et al, 2011), even for samples equivalent to half a cell (Figure 1B). These results demonstrate that our ddPCR‐based method can reliably quantify the copy number of T .…”